Perfluorocarbon induced intra-arrest hypothermia does not improve survival in a swine model of asphyxial cardiac arrest☆

Abstract 

Background

Pulseless electrical activity is an important cause of cardiac arrest. Our purpose was to determine if induction of hypothermia with a cold perfluorocarbon-based total liquid ventilation (TLV) system would improve resuscitation success in a swine model of asphyxial cardiac arrest/PEA.

Methods

Twenty swine were randomly assigned to control (C, no ventilation, n=11) or TLV with pre-cooled PFC (n=9) groups. Asphyxia was induced by insertion of a stopper into the endotracheal tube, and continued in both groups until loss of aortic pulsations (LOAP) was reached, defined as a pulse pressure less than 2mmHg. The TLV animals underwent asphyxial arrest for an additional 2min after LOAP, followed by 3min of hypothermia, prior to starting CPR. The C animals underwent 5min of asphyxia beyond LOAP. Both groups then underwent CPR for at least 10min. The endpoint was the resumption of spontaneous circulation maintained for 10min.

Results

Seven of 9 animals achieved resumption of spontaneous circulation (ROSC) in the TLV group vs. 5 of 11 in the C group (p=0.2). The mean pulmonary arterial temperature was lower in total liquid ventilation animals starting 4min after induction of hypothermia (TLV 36.3±0.2°C vs. C 38.1±0.2°C, p<0.0001). Arterial was higher in total liquid ventilation animals at 2.5min of CPR (TLV 76±12mmHg vs. C 44±2mmHg; p=0.03).

Conclusion

Induction of moderate hypothermia using perfluorocarbon-based total liquid ventilation did not improve ROSC success in this model of asphyxial cardiac arrest.

Abbreviations: VF, ventricular fibrillation, PFCs, perfluorocarbons, TLV, total liquid ventilation, ROSC, resumption of spontaneous circulation, ET, endotracheal, ABG, arterial blood gases, IVC, inferior vena cava, MAP, mean arterial pressure, SAP, systemic arterial pressure, HR, heart rate, PAP, pulmonary artery pressure, CVP, central venous pressure, CO, cardiac output, ECG, electrocardiogram, CPR, cardiopulmonary resuscitation, CPP, coronary perfusion pressure, LOAP, loss of aortic pulsations, ETCO2, end-tidal carbon dioxide, CR, compression rate, s, seconds, min, minutes

Keywords: CPR, Resuscitation, Cardiac arrest, Asphyxia, Defibrillation, Perfluorocarbons, Liquid ventilation